Soil problem? (Newly created woodland area)

We've noticed growths of green algae and mossy stuff appearing on top of the soil in our woodland garden. We dug it over completely in the late spring and we're in the process of creating a woodland area. There is dappled shade from a neighbour's oak, trees in the wood at the back of the garden and hazels and conifers in the other neighbour's garden, but ours now has more sunlight since we had our evergreen removed last year. We're hoping for a woodland glade, but more managed, with a mixture of plants and flowers - some native, but all planted to attract wildlife. It's taking shape and this autumn we will plant a golden-berried viburnum opulus and a damson tree.

All that sets the scene. But should we be worried by the algal growth? I've noticed it somewhere else where I dug in the last couple of months. Is it harmful. and if so, what can we do about it?